Between 2002-2004 and 2008-2010, past year heroin use increased among people reporting past year nonmedical use (PYNMU) of opioid pain relievers, but not among those reporting no PYNMU. Frequent nonmedical users – people reporting 100-365 days of PYNMU – had the highest rate of past year heroin use and were at increased risk for ever injecting heroin and past year heroin abuse or dependence as compared to infrequent nonmedical users (1-29 days of PYNMU).

In 2008-2010, 82.6% of frequent nonmedical users who used heroin in the past year reported nonmedical use of opioid pain relievers prior to heroin initiation compared to 64.1% in 2002-2004.